Anti-friction bearings (also commonly known as rolling-contact bearings), such as ball bearings and tapered roller bearings, are commonly used in various industrial applications. Anti-friction bearings are typically purchased preassembled, ready for press fit onto the journal of a shaft or axle.
A lubricant (e.g., oil or grease) is applied to the bearing's rollers to minimize friction and wear. The quantity and quality of the lubricant has a significant effect on bearing life. To maximize the life of the bearing, bearing seals are used to retain lubricant within the bearing and exclude environmental contaminants. A good seal design strives to protect the bearing lubricant while balancing the need to minimize friction losses resulting from the bearing seal.
Bearings used in the railway industry to support railway car axles are a particularly demanding application, requiring energy efficiency while concurrently providing protection against environmental contaminants (such as water, dirt, sand etc.). These bearings must also effectively seal the bearing to minimize lubricant loss.